PENDLETON, Ore. (AP) — Investigators on Monday picked their way through a gutted Oregon house where five people died and two were seriously burned, but they found no initial indication of arson.

Pendleton Police Chief Stuart Roberts said no cause had been ruled out. The investigation began after daylight Monday because the two-story house in the eastern part of the state was too dangerous to examine in the dark, he said.

“Pretty much all that’s left is the floor joists,” Roberts said.

The two survivors are on breathing tubes at a Portland hospital and considered in critical condition, so authorities have not yet talked to them, he said.